Morepath is a micro web framework with a model-driven approach to creating web applications and web APIs.
Morepath's framework philosophy is that the data models should drive the creation via the web framework. By default the framework routes URLs directly to model code, unlike for example Django which requires explicit URL routing by the developer.
Simple CRUD web applications and APIs can be tedious to build when they are driven straight from data models without much logic between the model and the view.
With the rise of front end JavaScript frameworks, many Python web frameworks are first being used to build RESTful APIs that return JSON instead rendering HTML via a templating system. Morepath appears to have been created with the RESTful API model approach in mind and cuts out the assumption that templates will drive the user interface.
On the Morepath is a blog post by Startifact on how they use Morepath and some of the features of the framework.
Morepath's creator gave a great talk on the motivation and structure for the new framework at EuroPython 2014.